Chemical Constituents From The Lianas Of Gnetum Cleistostachyum And Gnetum Brunonianum & Biomimetic Synthesis Of Active Oligostilbenes

Naturally occurring oligostilbenes are a type of compounds with complex structures and multi-faced bioactivities, polymerized from stilbene monomers with different type or degree. In recent years, more and more oligostilbenes isolated from natural resources enriched greatly the content of oligostilbenes in structures and amount. This research field is attracting the attentions of researchers from all over the world.We have made a progress on the basis of the bioactivities and mimic biosynthesis of naturally occurring oligostilbenes, as well as the natural stilbene derivatives. The chemical constituents of two Gnetaceae species and biomimetic synthesis of active oligostilbenes were investigated. Pharmacological activities of some oligostilbenes have been tested. The relationships between the reaction activity of stilbene monomers and the distribution of naturally occurring oligostilbenes, and their structure-activity relationships on TNF-α inhibitory activity were also discussed.33 compounds, including 11 new compounds and 22 known components, were isolated from Gnetum. cleistostachyum C. Y. Cheng and Gnetum brunonianum Griff, respectively.From the lianas of G. cleistostachyum, 10 new compounds, named gnetucleistol A-H, (+)-bisisorhapontigenin A and czs-shegansu B (three stilbenolignanes, two stilbene dimers, four stilbene momomers and a new stilbene derivative), together with 17 known compounds have been isolated. Gnetucleistol F (1) and H (2) are novel stilbenolignanes constructed by the linking of a stilbene unit and a phenylpropenol unit forming dihydrobenzofuran ring. Gnetucleistol G (3) is a new stilbenolignane with 3-oxabicyclo [3. 3. 0] octane ring system. Gnetucleistol A (4) is a new stilbene derivative condensed by an isorhapontigenin and a benzene derivative with dihydrobenzofuran ring. Cis-shegansu B (5) is a cis isomer of shegansu B. (+)-bisisorhapontigenin A (6) is isolated as a natural product for the first time. Gnetucleistol B (7) is the first cis stilbene isolated from the genus Gnetum. Gnetucleistol C (8), D (9) and E (10) are new stilbene monomers.